my british blue likes to wee up the side of the sofa especially in winter when it's cold and can't be bothered to go outside we try and stop him by shooing him away.
when his tail starts to shake I'm wondering is there any way to stop this any sprays you can buy for the furniture any advice would be appreciated.

If they've peed in one area, they tend to continuing going there because they can smell it so to them; smell of wee = my toilet. Is he actually toileting or just scenting? If he has been done, it won't smell and nothing really comes out, but he doesn't know that of course.

Make sure you deep clean it to get the smell out and whenever he goes to pee there use a deterrent such as an air blower, gentle water spray bottle and make sure you are consistent with it, he will soon learn that that is not his toilet. If he is actually peeing and not just scenting immediately place him in his tray or outside when he does it so he learns that if he wants to do that, this is where he has to go.

Do you not have a litter tray in the house? Use a solution of bio washing powder and water to clean the area, the enzymes in the washing powder kills the smell that makes a cat return to the same place to pee.

Get some citrus stuff. Depending on where it is either air freshener or shake n vac.
Cats hate the smell and as it's overpowering won't want to go near it.

Worked with ours. Hope this helps.

Is he neutered?

Remember when he's not doing in your house ,he'll be doing it in someone else's garden and it stinks!

Sounds like he's spraying to mark his territory rather than weeing. If he's not neutered get him done ASAP. Muze is correct, he'll be marking everywhere he goes and it reeks to high heaven. Very frustrating if a local Tom chooses your doorway to spray in. Not to mention the numerous females he'll be knocking up when he's out and about. Neutering usually prevents it but if he's reached full maturity it might not be fully successful.

Feliway?

Your cat might be stressed.